Crystal and Molecular Structure of 2,3,5,6-Bis(ortho-1,10-decylidene)dihydropyrazine

作     者：WANG Ming-An ZHANG Ning HOU Xue-Tai WANG Dao-Quan 

作者机构：Department of Applied Chemistry China Agricultural University Beijing 100094 China 

出 版 物：《Chinese Journal of Structural Chemistry》 (结构化学（英文）)

年 卷 期：2005年第24卷第11期

页      面：1254-1258页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070303[理学-有机化学] 0703[理学-化学] 

基　　金：This project was supported by the National Natural Science Foundation of China (No. 20072053) 

主　　题：2,3,5,6-bis(ortho-1,10-decylidene)dihydropyrazine crystal structure NMR 

摘      要：The SnCl2 reduction of 2-nitrocyclododecanone or 2-bromo-12-nitrocyclododecanone gave a colorless compound 2,3,5,6-bis（ortho-1,10-decylidene）dihydropyrazine 1a characterized by IR, NMR and X-ray diffraction analysis. Crystal data for 1a： Mr = 358.60, monoclinic, space group P2 1/n, α = 0.48028（3）, b = 2.8646（4）, c = 0.77097（6） nm, β = 98.432（12）°, V = 1.04924（19） nm^3, Dc = 1.135 g/cm^3, Z = 2, F（000） = 400 and μ（MoKa） = 0.065 mm^-1. All ^1H- and ^13C-NMR resonance lines of 1a were assigned by DEPT, COSY, HMQC and HMBC technology. In the crystal, the dihydropyrazine ring has a planar structure, two twelve-membered tings adopt [lene2333] conformation, their double bonds have cis-configuration, and the whole molecule has a center of symmetry. In solution, the symmetric ^1H- and ^13C-NMR signals suggest that two twelve-membered rings of 1a may adopt enantiomorphous [ lene2333] conformation existing in a dynamic equilibrium.